Epitaxial Growth and Optical Properties of Laser Deposited CdS Thin Films

In this study, cadmium Sulfide (CdS) thin films were synthesized on quartz substrates using an infrared pulsed laser deposition (IR-PLD) technique under high vacuum (~10−6 Torr) conditions. X-ray diffraction was used to evaluate the structural features. According to X-ray analysis, the deposited CdS films are crystalline and have a favored orientation on a plane (110) of an orthorhombic. The peak intensity and the average crystallite size increases with increasing the film thickness. After annealing at 300 °C, the orthorhombic phase transformed into a predominant hexagonal phase and the same result was obtained by SEM photographs as well. Spectrophotometric measurements of transmittance and reflectance of the CdS films were used to derive optical constants (n, k, and absorption coefficient α). The optical band gap energy was found to be 2.44 eV. The plasma plume formation and expansion during the film deposition have also been discussed. The photocurrent response as a function of the incident photon energy E (eV) at different bias voltages for different samples of thicknesses (85, 180, 220 and 340 nm) have been studied, indicating that the photocurrent increases by increasing both the film thickness and photon energy with a peak in the vicinity of the band edge. Thus, the prepared CdS films are promising for application in optoelectronic field.

Synthesis, Properties and Aging of ICP-CVD SiCxNy:H Films Formed from Tetramethyldisilazane

Amorphous hydrogenated silicon carbonitride films were synthesized on Si(100), Ge(111), and fused silica substrates using the inductively coupled plasma chemical vapor deposition technique. 1,1,3,3-tetramethyldisilazane (TMDSN) was used as a single-source precursor. The effect of the precursor’s pressure in the initial gas mixture, the substrate temperature, the plasma power, and the flow rate of nitrogen gas as an additional reagent on the film growth rate, element composition, chemical bonding, wettability of film surface, and the optical and mechanical properties of a-SiCxNy:H films was investigated. In situ diagnostic studies of the gas phase have been performed by optical emission spectroscopy during the film deposition process. The long-term stability of films was studied over a period of 375 days. Fourier-transform infrared (FTIR) and X-ray energy dispersive spectroscopy (EDX), and wettability measurements elucidated the oxidation of the SiCxNy:H films deposited using TMDSN + N2 mixture. Films obtained from a mixture with argon had high stability and maintained the stability of element composition after long-term storage in ambient air.

Peculiarities of the Acoustic Wave Propagation in Diamond-Based Multilayer Piezoelectric Structures as “Me1/(Al,Sc)N/Me2/(100) Diamond/Me3” and “Me1/AlN/Me2/(100) Diamond/Me3” under Metal Thin-Film Deposition

New theoretical and experimental results of microwave acoustic wave propagation in diamond-based multilayer piezoelectric structures (MPS) as “Me1/(Al,Sc)N/Me2/(100) diamond/Me3” and “Me1/AlN/Me2/(100) diamond/Me3” under three metal film depositions, including the change in the quality factor Q as a result of Me3 impact, were obtained. Further development of our earlier studies was motivated by the necessity of creating a sensor model based on the above fifth layered MPS and its in-depth study using the finite element method (FEM). Experimental results on the change in operational checkpoint frequencies and quality factors under the effect of film deposition are in satisfactory accordance with FEM data. The relatively small decrease in the quality factor of diamond-based high overtone bulk acoustic resonator (HBAR) under the metal layer effect observed in a wide microwave band could be qualified as an important result. Changes in operational resonant frequencies vs. film thickness were found to have sufficient distinctions. This fact can be quite explained in terms of the difference between acoustic impedances of diamond and deposited metal films.

Study of the influence of diamond-like carbon film deposition technology on the change of its physical and mechanical characteristics

The paper presents the results of testing the technology of deposition of diamond-like carbon films on the surface of stainless steel substrates at different process parameters, a quantitative assessment of the sp3 bond content and the physical and mechanical characteristics of the coatings obtained, a conclusion about the influence of the deposition process technological parameters on these characteristics is formulated.

Current Approach to Develop TiO2 Thin Film as Photocatalysts for Low-Density Plastic Degradation

Low-density plastic bags waste disposal is a big issue in the current scenario which gives rise to grave threats to human beings and environmental health also. Amid the various approaches applied for dealing with the problem, photocatalytic biodegradation in visible light irradiation is an advanced prospect that has received attention nowadays. The present review paper is to provide an outline of the current progress on the synthesis of titania (TiO2) thin-film photocatalysts for solid waste removal. The Photocatalysis method contains the photoinduced redox reactions in the photocatalyst which facilitates the degrading of almost organic compounds like polyethylene into carbon dioxide (CO2), water, and other substance. One of the most excellent photocatalysts which has grabbed attention in an application is titania because of its high photocatalytic activity and chemical stability. The synthesis of the photocatalyst as a thin film is a result of the unfeasible application of conventional powder photocatalyst which may cause a certain environmental hazard. The photocatalyst-coated thin film along with some environmental applications have also been reviewed. Likewise, various approaches for modifying thin-film property, film deposition techniques, and deposition on various substrates are used for the enhanced photocatalytic activity of the TiO2 thin film.

High-frequency rectifying characteristics of metallic single-electron transistor with niobium nanodots

Metallic single-electron transistors (SETs) with niobium nanodots were fabricated, and their high-frequency rectifying characteristics were evaluated. By reducing the gap size of the electrodes and film deposition area to nanometer scale, improved SET characteristics with gate control, and better frequency response of the rectifying current with gentler decrease than 1/f at high frequency were achieved. The comparison between the characteristics of micrometer- and nanometer-size devices are made, and the reason for their differences are discussed with a help of simulation based on the experimentally extracted parameters.